Only update a document's _id and _rev if the save was successful.

Thanks Jason Davies.

git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@793218 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/jquery.couch.js b/jquery.couch.js
index 3c629e1..e974a3c 100644
--- a/jquery.couch.js
+++ b/jquery.couch.js
@@ -239,9 +239,9 @@
             dataType: "json", data: toJSON(doc),
             complete: function(req) {
               var resp = $.httpData(req, "json");
-              doc._id = resp.id;
-              doc._rev = resp.rev;
               if (req.status == 201) {
+                doc._id = resp.id;
+                doc._rev = resp.rev;
                 if (options.success) options.success(resp);
               } else if (options.error) {
                 options.error(req.status, resp.error, resp.reason);